1. Field of the Invention
The present invention relates to tetrahydrofuran derivatives and a process for their production. More particularly, it relates to tetrahydrofuran derivatives having a novel structure, which are useful as aprotic polar solvents or as starting materials for organic fine chemicals, and a process for their production.
2. Discussion of Background
As aprotic polar solvents having high dielectric constants, N-methyl-2-pyrrolidone, dimethyl acetamide and dimethyl sulfoxide have been known. However, these compounds contain hetero atoms such as nitrogen atoms or sulfur atoms, or reactive ketone groups. Therefore, their applications have been rather restricted.
On the other hand, as a compound having only ether linkages without containing nitrogen or sulfur atoms, (S,S)-(-)-3,4-dimethoxytetrahydrofuran has been known, wherein the two methoxy groups take a trans form to the plane of the tetrahydrofuran ring. This compound can be produced from (R,R)-(+)-2,3-dimethoxysuccinic acid ethyl ester, as disclosed in Helvetica Chemica Acta, vol. 60, p. 303 (1977), but the dielectric constant is not disclosed.